Blend tool is not blending

Hi, I'm running into a problem with the Blend tool, having two objects that are separated letters in a circle shape. They completely repeat each other, but have a different size. The smaller one is under the larger one. Their centers are superimposed on each other. The essence of the problem is that the Blend tool simply refuses to work, the program writes that the tool is not available. I have no idea how to solve this problem, because I work in Adobe Illustrator for the first time in my life. Please help, important project.